Marin beaches receive ace grades for summer water quality

Ripples cross Horseshoe Cove at Fort Baker in Sausalito on Friday, July 9 2021. (Alan Dep/Marin Independent Journal) 

The ongoing historic drought has had many negative consequences for Marin County so far but has led to one short-term benefit: cleaner beach water during the summer.

Twenty-four beaches tested in Marin County received straight-A grades for water quality during the summer of 2020 as part of the latest Beach Report Card released by the Santa Monica-based environmental group, Heal the Bay. The organization grades beaches based on concentrations of fecal bacteria contamination such as E. coli, which can indicate the potential presence of harmful pathogens.

Marin’s beaches were among the 93% of the 500 statewide beaches assessed in the report that received high marks for the summer of 2020, namely because of the below-average rainfall in the summer before, according to water quality officials.

“That reduced the amount of pollutants flowing out to the ocean,” said Arti Kundu, who heads the beach water quality testing program for the Marin County Environmental Health Division. “Whenever there are drought conditions or a decrease in the rainfall, we always have improved water quality.”

The reverse scenario plays out as well. Heavy rains lead to more runoff of pollutants onto beaches during the winter months.

However, Marin does not test water quality during the winter period of November through the end of March since it began its beach monitoring program in 2003, Kundu said. The reason is because of the state grants that fund these beach water tests, Kundu said.

To qualify for the funds, the tested beaches must meet several criteria. It must be used by 50,000 people per year for recreational purposes in which people regularly come in contact with the water, such as swimming and have an identified source of contamination near it such as a sewage system.

A National Park Service lifeguard patrols Stinson Beach on Thursday, April 1, 2021. (Sherry LaVars/Marin Independent Journal) 

The winter months typically see a significant reduction in beach visitors and recreation.

“That’s the main reason we stop during the winter months,” Kundu said.

For California beaches that were tested during the winter months, the grades were worse than average, according to Heal the Bay.

Typically, a significantly dry winter such as occurred in 2020-21 would lead to less pollutant runoff. The group attributes this abnormal occurrence to receiving 1,500 fewer water samples than normal, which it says can skew the results. A more significant factor is that the drought led to fewer chances for people to test for winter water quality, so many tests were done during the first major flushes of rain that tend to have higher concentrations of bacteria.

Such was observed at several locations in the Point Reyes National Seashore near dairy ranches this past winter. The environmental group Western Watersheds Project contracted two days of water quality tests after the first major rains in January and found bacteria levels up to 300 times larger than the state health standards at one location. The group attributes this contamination to nearby cattle ranching operations …read more

Source:: The Mercury News – Entertainment


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